1. Field of the Invention
The present invention concerns a noncontact ID (identification information) card and a method of manufacturing of the same and, more particularly, a noncontact ID card in which the conduction state between both electrodes can be kept satisfactory for a prolonged period of time, even in case of bonding between an antenna electrode of an antenna circuit board and an enlarged electrode of an interposer board with electroconductive adhesive material, and a method of manufacturing of the same.
2. Detailed Description of the Prior Art
Conventionally, those on various forms are well known, as a noncontact ID card, a noncontact ID tag and so on mounting an IC chip on an antenna circuit board. As a representative example thereof, the International Publication (WO01/62517) can be cited, and the noncontact ID card disclosed in this document is a noncontact ID card in which an antenna circuit board where an antenna is formed and an interposer board formed by connecting an enlarged electrode to an electrode of an IC chip mounted thereof are laminated and, at the same time, an antenna electrode of the antenna circuit board and the enlarged electrode of the interposer board are bonded with electroconductive adhesive material.
However, the portion where both electrodes are bonded with the electroconductive adhesive material might come off under the effect of temperature, moisture and so on and it is extremely difficult to hold the bonding state in a conduction state of a constant electric resistance for a prolonged period of time. Especially, as the bonding part of both electrodes is minute in area, it has been difficult to resolve it so long as general commercialized electroconductive adhesive material is used.
Moreover, as for electroconductive adhesive material, those of paste form or film form containing a number of electroconductive particles in resin are used. When this electroconductive adhesive material is used for bonding between both electrodes, it is painted and dried on the electrode of the interposer board in case of paste form before bonding them, and sticked in case of film form. Next, this interposer board is laminated on the antenna circuit board, points where both electrodes are opposed are heated under the pressure by a heat tool, and both electrodes are bonded in a conduction state through heat sealing.
However, in the initial phase immediately after the start of heat sealing, as both electrodes are in an unstable temporary bonding state one to the other, a miss-alignment may occur between the bonding positions of both electrodes due to fluidity, elasticity and so on of the resin component of the electroconductive adhesive material. Then, if the flatness between both electrodes can be no more kept precise due to the dislocation of this bonding part, there is a problem that the electric resistance value of the bonding part changes, and thereby resulting in the production of defectives.